Preliminary Design

Before developing our solution, we first examined the two important types of peanut shellers available. The first is the Universal Nut Sheller which is easy to build and has a simple design, but is heavy and not portable due to its concrete construction. It also requires expensive fiberglass molds. The other main design is the large decorticators of commercial design. These machines have a high capacity, have a state of the art design, but are expensive, require external power and are very large. These devices are therefore inadequate for use by the Zambians.

Our device must be an inexpensive as possible in order for the maximum about of Zambians to benefit. For this reason, our design solution is almost entirely made of wood with a few other inexpensive components. We have also adopted a modular design that allows for continuous operation by two people, while also allowing the modules to be separated and used by different tribe members.

Our device must be an inexpensive as possible in order for the maximum about of Zambians to benefit. For this reason, our design solution is almost entirely made of wood with a few other inexpensive components. We have also adopted a modular design that allows for continuous operation by two people, while also allowing the modules to be separated and used by different tribe members.

Preliminary Design (SolidWorks Model)

The first module is the crusher. This module consists of a treadmill positioned over an inclined surface. Peanuts slide under the tire aided by gravity, and are then pulled along by the hand crank-powered treadmill, which is positioned over the inclined surface with an adjustable clearance gap between the inclined surface and the belt, through which peanuts travel. The treadmill forces the peanuts into a rolling motion between the surface of the belt and the surface of the inclined surface. The resulting rolling motion is the key to this design, as it causes torsion within the peanut shell and effectively crumbles it, completely removing it from the seed and leaving the seed intact. The crusher module is powered by a simple wooden hand crank. This crank is attached to the square axel of the lower wheel. The rubber belt (probably a tire with the sidewall cut away) loops around the two wheels and is held taught by them. The movement of the first wheel moves the belt, which in turn rotates the second wheel on its axel. The entire wheel mechanism is attached to the base unit, made of wood, via its adjustable bolts. This allows the gap size to be optimized for the nuts being crushed.

The separation module uses the flapping of single flat board as a wind source to separate the seed and shell. This board will be balanced on a pivot point. By rocking one end of the board with one’s foot, the other end will create wind flow through the horizontal tunnel of the device. The mixture of shell and seed from the crusher falls into this wind tunnel and is pushed along by the air flow through it. Lighter husks blow through the end of the tube where as heavier sees roll along the bottom of the tunnel and into a basket at the end of the tunnel. This method improves upon the traditional method of winnowing by generating a controlled wind source to aid in the separation process.